Overwrappers for cylindrical bodies and in particular overwrappers for products which can be easily opened but at the same time should be protected from dirt, dust, moisture or other contamination while wrapped such as, for example, catamenial tampons are popular ways to provide individual, portable articles. While the invention will be discussed specifically in terms of catamenial tampons, it will be understood that the problems toward which this invention is directed and their solution applies to many similar products, including, for example, foods, tobacco products and the like.
One method and apparatus for closing a packing tube is disclosed in WO 01/36272 (Buzot et al). In this publication, a packing tube is closed around an essentially cylindrical packaged product. The packing tube is projected beyond a free forward end of the product is pressed together and joined by heated clamping jaws to form a first film sheet. The formed first film sheet portion is then folded over and laid onto the outer surface of packing tube at the forward end. Sealing of the folded sheet is accomplished by application of heated dome shaped pressing head. The inner walls surrounding the recess of the heated pressing head melts the folded sheet with the film of the outer surface of the packing tube. Sufficient heat needs to be applied to melt the three layers of film together. Additionally, the heated jaws need to conform to the geometry or curvature of the insertion end of the tampon in order for the melted film to provide a tight fit of the overwrap.
New development in catamenial tampons now include those that have covers or fluid transport plates such as those disclosed in US 20050256511, US 20050283128 and WO 2005/112860. In these new types of tampons, by-pass leakage is reduced as the fluid transport plates serve to direct fluid to a fluid storage element. One example of such a tampon is one that includes as fluid transport plates a sheet of apertured film, which covers the insertion portion of the fluid storage element and is attached to the fluid storage element by a longitudinal heat seal. This differs from previous tampons in many ways, including the fact that an apertured film covers the insertion portion of the tampon, which typically has been left uncovered. WO 01/01909 discloses a domed tampon having an absorbent structure substantially enclosed by an apertured film cover that has a nonionic surfactant at least partially applied to the cover. The cover overlaps the domed-shaped introduction end but does not completely cover it. One problem encountered in the type of tampon that has a meltable material at the insertion portion of the tampon relates to providing and heat sealing an overwrap. The heat sealing of the overwrap generally occurs at the insertion end and withdrawal end. When heat is supplied to the overwrap material, the apertured film covering the insertion portion of the tampon is also subjected to the heat. The film may melt, the apertures may close and the film may become attached to the overwrap.
What is needed therefore, is a way to seal the overwrap without melting the apertured film covering the insertion portion of the tampon. In particular what is needed is a way to seal a cover or fluid transport element made of a material having a melting point equal to or less than the melting point of the overwrap. One difficulty in overcoming this problem is the geometry of the insertion end of the tampon. This invention solves this problem and provides an overwrapped catamenial device, a method for overwrapping a catamenial device and an apparatus useful for providing this overwrapped catamenial device.